New research presented at the ASCO Genitourinary Cancers Symposium 2026 has raised fresh questions about the potential link between microplastics and cancer — in this case, prostate cancer.

In a small study, researchers detected microplastics in prostate tissue from 9 of 10 men undergoing radical prostatectomy. Notably, concentrations of microplastics were higher in tumor tissue than in benign tissue.

“This is very early data from a pilot study of only 10 patients with prostate cancer, so we cannot make any causal conclusions,” lead investigator Stacy Loeb, MD, MSc, PhD, professor of urology and population health at NYU Grossman School of Medicine and NYU Langone Health, New York City, told Medscape Medical News.

Nonetheless, “We already know that plastics are bad for the environment and have other negative health impacts, so I think it’s safe to recommend that all of us should try to reduce unnecessary use of plastics,” Loeb said.

Emerging Data on Health Impacts

Microplastics — tiny plastic particles that result from the breakdown of larger plastics — have been detected in air, water, food, and human tissues — including the lungs, liver, blood, brain, and heart.

As previously reported by Medscape Medical News, a recent landmark study found that patients with microplastics detected in carotid artery plaque had a higher risk for death or major cardiovascular events than those with plaques where plastic particles were not found.

Other studies have shown links between microplastics and placental inflammation and preterm births, reduced male fertility, and endocrine disruption.

Although research on microplastics and cancer is still very early, research points to a possible link between microplastic exposure and carcinogenic processes, both in experimental systems and in epidemiologic observations.

For example, microplastics can infiltrate cells, induce oxidative stress, trigger chronic inflammation, and disrupt normal cellular pathways — all processes that are known to be involved in carcinogenesis, stated in a study published in Cell Biochemistry and Biophysics.

One recent study linked microplastic exposure to accelerated spread of cancer cells in the gastrointestinal tract.

The study by Loeb and colleagues included patients (median age, 65 years) undergoing radical prostatectomy. The researchers analyzed tumor and benign samples visually and then used specialized equipment to determine the amount of microplastic particles, as well as their chemical composition and structure, in the tissue. They focused on 12 of the most common types of plastic molecules.

The researchers identified plastic particles in 90% of tumor samples and 70% of benign tissue samples. The tumor samples contained on average 2.5 times the amount of plastic as the healthy prostate tissue samples — about 40 μg of plastic per gram of tissue compared with 16 μg/g.

Commonly identified particles included polyethylene, polyethylene terephthalate, and polypropylene-polyethylene copolymers.

A Cause for Concern?

Two ASCO experts told Medscape Medical News the findings are intriguing but hypothesis-generating.

These “provocative” results raise an “important question regarding the potential role of microplastics in prostate carcinogenesis,” William Kevin Kelly, DO, chair of the Department of Medical Oncology at Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, said.

Kelly stressed that validation in larger, well-characterized patient cohorts, along with mechanistic studies, is needed to “elucidate the biological pathways by which microplastic exposure may contribute to malignant transformation within the prostate.”

Echoing his colleague, William Oh, MD, director of precision medicine at Yale Cancer Center, New Haven, Connecticut, described the study by the NYU team as “provocative but preliminary.”

“There is a suggestion that microplastics are associated with cancer tissue compared with benign tissue in the same prostate samples,” but it’s “too soon to say that there is a causative relationship,” Oh said.

Oh also highlighted the variability within the small cohort, noting that in two patients, benign tissue contained more microplastic than cancer tissue. Even so, he said the findings “deserve further study.”

“In the meantime, avoiding certain behaviors that may increase microplastics in your body is reasonable — for instance, don’t microwave hot food in plastic containers, use steel water bottles, and avoid highly processed foods. While that may not prevent prostate cancer, these are small changes that may decrease your exposure until more is known,” Oh said.

Loeb told Medscape Medical News her team has received funding from the US Department of Defense to expand their research to 30 patients with prostate cancer. They plan to look at whether microplastics are associated with inflammation as a potential mechanism for carcinogenesis.

As larger studies move forward, the researchers hope to determine whether microplastics are merely bystanders in human tissue or active participants in disease development.

Funding for the study was provided by the US Department of Defense. Loeb reported consulting for a pharmaceutical company Astellas, digital health company Savor Health, and men’s health organization Movember; receiving research support from Endo USA, Inc.; and participating in advisory boards for Endo USA, Blue Earth Diagnostics, Pfizer, Sumitomo Pharma, and Doceree. Kelly and Oh reported having no disclosures.